Polymers of acyloxyalkyl substituted oxazolines



United States Patent 3,483,145 POLYMERS (1F ACYLOXYALKYL SUBTITUTEDOXAZGLINES ABSTRACT OF THE DESCLOSURE This invention relates to noveloxazolines having acyloxyalkyl substituents on the 2-position andpolymers pre pared from these compounds.

In accordance with the present invention, novel2-substituted-Z-oxazolines have been discovered which containacyloxyalkyl groups as the Z-Substituent. These compounds arerepresented by the formula 0 OCH2 Ri lO(CH- =)nC N-CH2 wherein Rrepresents an alkyl, aryl, alkaryl or aralkyl radical, and n is aninteger from 1' to 15. Preferably R represents a radical having up to 12carbons with particularly outstanding results being obtained when R isan alkyl group of from 1 to 5 carbon atoms. These compounds can bepolymerized to form polymers having recurring units of the formula o [IC-R wherein R and n are as defined above. These polymers have anacyloxyalkanoyl group side chain on each and every nitrogen atom in thebackbone. The polymers are amorphous when n has a value of 1 to 8.Polymers of the above formula can be modified by heating them withalkali to replace the acyl groups with hydroxy groups.

The compounds of this invention can be prepared bycyclodehydrohalogenation of the corresponding N-(tlhaloethyl) amides.These N-(B-haloethyhamides can be prepared from the correspondingacyloxyalkyl acid chloride or acid bromide by reaction withethylenimine, as illustrated in the following equation:

The polymerization of the heterocyclic iminoethers of the invention canbe carried out by heating them in an inert atmosphere in the presence ofa cationic catalyst such as alkyl halides, boron-fluorine compounds,antimony-fluorine compounds, strong acids, salts of strong acids, withan oxazoline or an oxazine, carbonic acid anhydrides, iodine, esters ofstrong acids, strongly acidic ion exchange resins, acid activated clays,tin halides and aluminum halides. Illustrative of catalysts that can beemployed are methyl iodide, 1,4-dibromobutane, boron tri-fluorideetherate, antimony pentafluoride, p-toluene sulfonic acid, sulfuricacid, nitric acid, perchloric acid, hydro bromic acid, hydroiodic acid,dimethyl sulfate, methyl p-toluene sulfonate, the salt of2-phenyl-2-oxazine with perchloric acid, aluminum chloride, tin chlorideand the perchlorate salt of 2-(p-chlorophenyl)-2-oxazoline.

In general, a mol ratio of about 10 to about 10,000 mols of monomer permol of catalyst will be employed. Increasing the catalyst concentrationwill tend to lower the molecular weight of the resultant polymer. Thetemperature at which the polymerization is carried out may range fromabout "80 C. to about 250 C.; the preferred temperature range is fromabout 100 to about 200 C. The time required to polymerize the monomersof the invention may vary from several minutes to several days dependingupon the reactivity of the monomer, the temperature of polymerization,the type of catalyst and its concentration and the desired molecularWeight. Increasing the time of polymerization usually increases themolecular Weight of the resultant polymer.

In carrying out the polymerization, a single monomer can be used toporduce a homopolymer, or two or more different monomers within thescope of the invention can be used to produce copolymers. Additionally,a modification of the polymers of the invention can be obtained if themonomers defined herein are admixed with one or more monomers of theformula wherein R represents a hydrocarbon radical such as alkyl, aryl,aralkyl, alicyclic and alkenyl groups or a halogenated hydrocarbonradical. Preferably R is alkyl of 1 to 20 carbon atoms such as methyl,isobutyl, pentyl, heptyl, undecyl and heptadecyi; halogenated alkyl of 1to 20 carbon atoms such as dichloromethyl; trichloromethyl,pentafluoroethyl and pentadecafluoroheptyl; aryl such as phenyl andnaphthyl; halogenated aryl such as p-chlorophenyl; aralkyl such asbenzyl; alkylaryl such as tolyl; saturated alicyclic such as cyclohexyland alkylene such as decenyl.

where X is chlorine or bromine and n and R have the meanings givenabove. Cyclodehydrohalogenation can be carried out according to knownmethods such as those described by Wiley et al. in Chem. Reviews, 44,447-475 (1949), whereby the amide is reacted with sodium hydroxide orpotassium hydroxide in aqueous or water/alcohol solutions. Alternately,and preferably, the N-(fihaloethyl) amide is reacted with anhydroussodium carbonate at a temperature high enough to recover the desired'heterocyclic iminoethers by distillation. This method is disclosed in acopending patent application U.S. Ser. No. 450,163 of Taghi G. Bassirifiled Apr. 22, 1965, now US. Patent No. 3,331,851.

The properties of the polymers of the invention vary with the length ofthe alkylene group in the side chain. The polymers which are amorphousare soluble in common solvents such as methanol, ethanol, chloroform,ethylene glycol, chlorobenzene, Xylene, benzene, naphthenes and alkanessuch as decane and dodecane, and they can be solution cast into films.As the number of carbon atoms in the polymer side chain increases, thepolarity tends to diminish and solvents of decreasing polarity arepreferably selected. The hard polymers can be used for moldingcompositions and the like. Those polymers that are soft are useful asadhesives and as coatings and sizings for fabrics and paper.

In addition, the polymers described above can be hydrolyzed in solutionwith a base to form the corresponding hydroxy-substituted polymers whichhave linear backbone chains and are composed of recurring units of theformula wherein n has the meaning given above. Suitable bases includealkali metal hydroxides such as sodium hydroxide and potassiumhydroxide. The hydrolyzed polymers are crystalline and can be drawn intofibers useful in the manufacture of textiles. Some of these polymers arewa' ter soluble and are useful as thickening agents in Watersolublepaints and aerosols.

The invention can be further illustrated by the examples given below,but it is to be understood that the invention is not meant to be limitedto the details described therein.

In the examples, all percent is by weight. The reduced weight solutionsin m-cresol at 25 C.

EXAMPLE 1 428.4 grams (3.6 mols) of thionyl chloride were added slowlyto 329.1 grams (1.95 mols) of 6-acetoxyhexanoic acid, maintained at 3545 C. for 3 hours and allowed to stand at room temperature overnight.Excess thionyl chloride was distilled 01f and the product distilledunder vacuum.

6-acetoxyhexanoyl chloride was obtained in 40% yield .as a clear,colorless liquid having a boiling point of 87 94 C./0.5 mm. Infraredanalysis confirmed the proposed structure.

The results of elemental analysis were calculated for C H O Cl: C, 50.0;H, 6.8; Cl, 18.4. Found: C, 49.7; H, 6.8; Cl, 18.7.

100 grams (0.52 mol) or 6-acetoxyhexanoyl chloride, as prepared above,was charged to a oneliter flask fitted with a stirrer and a refluxcondenser. 700 milliliters of ethyl ether were added and 22.4 grams(0.52 mol) of ethylenimine dissolved in 150 ml. of ether were added atsuch a rate as to maintain the solution at reflux. After the additionwas finished, anhydrous hydrochloric acid was bubbled through thesolution for minutes. Upon evaporation of the solvent, 105.7 grams(86.3% yield) of product was obtained which was recrystallized twicefrom ether.

The final product was a white solid having a melting point of 38.5 39.5C. and was determined to be N-(,8- chloro ethyl) -6-acetoxyhexanamide.

Elemental analysis calculated for C H NO Cl: C, 51.0; H, 7.6; N, 6.0;Cl, 15.0. Found: C, 50.7; H, 7.8; N, 6.2; Cl, 14.7.

35.3 grams (0.15 mol) of N-(fi-chloroethyl)-6-acetoxyhexanamide and 11grams (0.105 mol) of powdered sodium carbonate were charged to a flaskfitted with a stirrer and distillation head and connected to a vacuumsource. The system was brought to 0.5 mm. Hg pressure and heated to 80C. when a gas was evolved and the pressure increased slightly. When thegas evolution sub- Monomer 2-(fi-pentanoyloxypentyl)-2-oxazoline2-(5-benzoyloxypentyl) -2-oxazol1ne 4 EXAMPLE 2 Product StartingMaterial G-pentanoyloxyhexanoic aeid2-(5-pentanoylcxypentyl)-2-oxazolinc. G-benzoyloxyhexanoic acid2-(5-benzoyloxypentyl-2-oxazoline. fi-(p-toluyloxy) hexanoic aeid2-[5-(p-toluyloxy)pentyl1-2-0xazoline. fi-phenylaeetoxyhexanoie acid2-(5phenylacetoxypentyl)-2-oxazoline. fi-lauroyloxyhexanoic acid2-(5-lauroyloxypentyl)-2pxazoline.

The general procedure of Example 1 is repeated substituting 1.95 mols of6-acetoxydodecanoic acid for the 6- acetoxyhexanoic acid. The productobtained is 2-(5- acetoxyundecyl)-2-0xazoline.

EXAMPLE 4 114.9 grams (0.84 mol) of 2-acetoxyacetyl chloride and 300 ml.of ether were charged to a flask fitted with a stirrer, addition funneland reflux condenser. 36.2 grams (0.84 mol) of ethylenimine were addedover a 2-hour period. The temperature reached 30 C. The solution wasthen cooled in a Dry Ice-acetone bath. A white solid was collected byfiltration and recrystallization from ether.

N-(fl-chloroethyl)-2-acetoxyacetamide was obtained in 98% yield. It hada melting point of 68.5 -70.5 C. This product was charged to a flaskfitted with a distillation head and 87.2 grams (0.82 mol) of anhydroussodium carbonate added. The mixture was heated at 65--115 C. under 17mm. Hg pressure and 107.5 grams of a clear, colorless liquid distilledover. This crude product was redistilled at 57 C./-0.05 mm. of Hg togive 2-acetoxymethyl-Z-oxazoline having the following elementalanalysis: Calculated C, 50.3; H, 6.3; N, 9.8. Found: C, 50.5; H, 6.3; N,9.7.

EXAMPLE 5 Portions of 2-(S-acetoxypentyl)-2-oxazoline, as prepared inExample 1, were distilled into two polymerization tubes. p-Chlorophenyloxazolinium perchlorate was added as catalyst at a mol ratio of monomerto catalyst of 120:1

- in the first tube and 1080:1 in the second. The tubes were2-[5-(p-toluy1oxy) pentyl1-2bxazoline 2-(5-phenylacetoxypentyD-2-oxazolm2-(5-lauroyloxypentyl) 2-(5-acetoxyundecyl)-2-oxazollne degassed andsealed.

The first tube was placed in an oil bath at C. for 4 hours and 20minutes. The product, poly [N-(fi-acetoxyhexanoyl)ethylenimine] was asoft yellow polymer. It had a reduced viscosity of 0.21.

The second tube was placed in an oven at C. for 24 hours.Poly[N-(6-acetoxyhexanoyl)ethylenimine] was obtained as a clear polymerhaving a reduced viscosity of EXAMPLE 6 Portions of the2-substituted-2-oxazolines prepared in Examples 2 and 3 are distilledinto polymerization tubes and admixed with p-chlorophenyl oxazoliniumperchlorate catalyst at a monomer-to-catalyst mol ratio of 108021. Thetubes are degassed, sealed and heated at 150 C. for 24 hours to formpolymeric products. The polymers are as follows:

Polymer PolylN-(B-pentanoyloxyhoxanoyl ethylenimine].

Poly[N-(G-p-toluyloxyhexanoyl) ethyleniminel.

. Po1y[N-(G-phenylacetoxyhexanoyl) ethylenimrne].

- Poly[N-(G-lauroyloxyhexanoyl) ethylenirnine].

Poly[N-(fi-acetoxydodeeanoyl) ethylenmnne].

EXAMPLE 7 Portions of 2-acetoxymethyl-Z-oxazoline, prepared as inExample 4, were distilled into two polymerization tubes andp-chlorophenyl oxazolinium perchlorate catalyst 75 added at a mol ratioof monomer-to-catalyst of 500:1

and 130011 respectively. The first tube was placed in an oven at 130 C.for 15 minutes. A yellow-brown solid polymer was obtained having areduced viscosity of 0.34.

The second tube was heated at 80 C. for 17 hours. A clear yellow solidwas obtained. The polymer had a reduced viscosity of 0.37.

The polymers were slightly soluble in water and soluble in methanol andethylene glycol.

Infrared analysis of both polymers confirmed the structure ofpoly[N-(2-acetoxyethanoyl)ethylenimine].

EXAMPLE 8 2.78 grams (0.0197 mol) ofpo1y[N-(2-acetoxyethanoyl)ethylenimine] were added to 50 ml. of waterand 0.78 gram (0.0197 mol) of sodium hydroxide was admixed therewith.When all the base was used up, as shown by an acid base indicator, thesolvent was evaporated and the polymer precipitated with methanol. Thepolymer was dried in a vacuum oven.

The product, poly[N (2 hydroxyethanoyl)ethylenimine], had a reducedviscosity of 0.21.

The structure was confirmed by infrared analysis. X- day examinationindicated a crystalline polymer.

EXAMPLE 9 A portion of poly[N-(G-acetoxyhexanoyl)ethylenimine] having areduced viscosity of 1.47 prepared as in Example 5 was dissolved inethanol and refluxed with an excess of sodium hydroxide. After about 5minutes, a white solid precipitated. After cooling to room temperature,the solid was filtered off and dried overnight at 45 C. under vacuum. Itwas identified as sodium acetate.

The filtrate was treated with ether and the white, powdery solid whichprecipitated was collected and dried under vacuum.

The product had a reduced viscosity of 1.47. The structure of poly[N-(6-hydroxyhexanoyl)ethylenimine] was confirmed by infrared analysis. AnX-ray spectrum indicated the polymer Was crystalline. Differentialthermal analysis confirmed the crystallinity of the polymer whichwherein R is a member selected from the group consisting of alkyl, aryl,alkaryl, and aralkyl radicals of up to 12 carbon atoms and n is aninteger from 1 to 15.

2. A polymer according to claim 1 wherein R is an alkyl radical havingfrom 1 to 5 carbon atoms.

3. A polymer according to claim 1 wherein R is a methyl group and n is5.

4. A polymer according to claim 1 wherein R is a methyl group and n is1.

5. A linear backbone chain polymer consisting essentially of recurringunits of the formula wherein n is an integer from 1 to 15.

6. A polymer according to claim 5 wherein n is 1. 7. A polymer accordingto claim 5 wherein n is 5.

References Cited UNITED STATES PATENTS 2,372,409 3/ 1945 Tryon 2603073,264,368 -8/1966 Lane et a1 2602 3,346,527 10/1967 Lagally 26023,373,194 3/1968 Fuhrmann et al 2602 3,375,231 3/1968 Fukui et al. 2602FOREIGN PATENTS 666,828 11/1'965 Belgium.

OTHER REFERENCES Seeliger et al.: Angewandte Chemie, International Ed.,vol. 5, October 1966, pp. 875-888, pp. 880-882 only needed.

Seeliger et al.: Angewandte Chemie, International Ed., vol. 5 June 1966,p. 612.

Wehrmeister: Chemical Abstracts, vol. 63 (1965), col. 610 (Abstract ofFrench 1,385,727).

Fieser et al.: Organic Chemistry, D.C. Heath and Co., Boston, pub.(1944), p. 182.

SAMUEL H. BLECH, Primary Examiner U.S. Cl. X.R.

